Introduction
Mileage is one of the first things any buyer checks, and for genuine reason, it's one of the clearest, most predictable drivers of a car's value. But the relationship isn't as simple as "more miles, less money," the shape of that curve, and a few real exceptions to it, are worth understanding properly before you value or sell your car.
This guide covers exactly how mileage affects value, the specific thresholds that matter most, and the genuine surprises, both high and low mileage, worth knowing about.
Summary:
- A common rule of thumb is a car losing around 20% of its value for every 20,000 miles driven, though this varies by model and isn't a straight line.
- Value drops steepest between 10,000 and 60,000 miles, then genuinely starts levelling off from around 100,000 miles onward.
- 30,000, 60,000 and 100,000 miles act as real psychological barriers for buyers, values often dip noticeably right as a car crosses each one.
- Unusually low mileage doesn't automatically mean a higher price. Buyers can question why a car's barely been driven, and genuine mechanical issues like perished seals and degraded fluids become more likely on cars that sit unused.
- Mileage matters more as a car ages. For cars under five years old, age tends to drive value more than mileage does, that balance flips the older a car gets.
The Basic Rule: Around 20% Per 20,000 Miles
A commonly cited rule of thumb puts a car's value loss at roughly 20% for every 20,000 miles it covers, though this varies considerably by make, model and the car's overall condition.
To make that concrete: a car bought new for £25,000 might be worth around £20,000 by 20,000 miles, roughly £16,000 by 40,000 miles, and around £12,800 by 60,000 miles, an illustrative pattern rather than a guaranteed figure for any specific car.
It's a useful starting point for a rough estimate, but genuinely not a precise formula, since so many other factors, service history, colour, and current demand among them, all interact with mileage rather than working in isolation.
Why Mileage Actually Causes Wear
It's worth understanding what's genuinely happening underneath a high mileage figure, not just that buyers dislike it. Brakes wear through friction between pads and discs, tyres sacrifice themselves for grip, and suspension components absorb every pothole and imperfection in the road, all wearing down measurably as the miles add up. Interior trim, steering wheels and seat edges show the same story from the inside.
Interestingly, a car's engine doesn't simply get worse with every mile from day one, most have a genuine "running-in" period early on, where a small amount of initial wear actually helps components settle and work together more smoothly. It's really sustained high mileage over time that brings the friction and wear that eventually makes an engine feel less responsive.
The Real Shape of the Depreciation Curve
Mileage doesn't erode value in a straight line. Independent research shows value drops most steeply between roughly 10,000 and 60,000 miles, the range where the bulk of a car's mileage-driven depreciation actually happens. Past around 100,000 to 110,000 miles, that rate of decline genuinely slows down considerably, a car that's already lost much of its value has less further to fall.
The Psychological Thresholds Worth Knowing About
Buyers genuinely think in round numbers, and 30,000, 60,000 and 100,000 miles act as real psychological barriers. A car sitting just under one of these figures often achieves a noticeably better price than an otherwise identical car that's just crossed it, even when the actual difference in wear is negligible.
If you're planning to sell, it's genuinely worth timing it before you cross a threshold rather than just after.
Why Very Low Mileage Doesn't Always Mean a Higher Price
This genuinely surprises a lot of sellers. A car with unusually low mileage for its age doesn't automatically command a premium, and the gap can be smaller than you'd expect, sometimes only a few hundred pounds more than a car with meaningfully higher mileage.
Buyers can be genuinely wary of a car that's barely been driven, questioning why, and whether it's spent long periods sitting unused. That matters mechanically too, seals can perish, brake components can corrode, and fluids degrade over time regardless of how few miles a car's actually covered, real risks a buyer or dealer will factor into their offer.
Age vs Mileage: Which Actually Matters More?
The balance genuinely shifts as a car gets older. For cars under five years old, age tends to be the bigger driver of value, two cars of a similar age with somewhat different mileage often aren't worth wildly different amounts.
Once a car passes five years old, mileage starts to matter proportionally more, and the gap between a low-mileage and high-mileage example of the same age widens considerably.
The Type of Mileage Matters Too
Not all miles wear a car out equally. Stop-start city driving, with its constant gear changes and clutch use, genuinely puts more strain on a car than the same distance covered at a steady motorway cruise.
It's part of why two cars with identical odometer readings can be in noticeably different mechanical condition, and it's worth mentioning honestly in your listing if the bulk of your mileage was gentler motorway driving rather than stop-start urban use.
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Conclusion
Mileage genuinely is one of the clearest signals of a car's value, but it's a curve rather than a straight line, steepest early on, levelling off at higher figures, and shaped by real psychological thresholds along the way.
Understanding where your own car sits on that curve, and being honest about the type of driving behind its mileage, gives you a genuinely realistic picture before you sell.
If you'd rather skip the guesswork, Cardaddys gives you a real, up-to-date valuation reflecting exactly where your car sits today.
Frequently Asked Questions
How much does mileage actually reduce a car's value?
A common rule of thumb is around 20% for every 20,000 miles, though this varies by make and model and isn't a straight line, the steepest drop happens between roughly 10,000 and 60,000 miles.
Is it worth selling my car just before it crosses a mileage threshold?
Genuinely, yes, worth considering. Buyers think in round numbers, and 30,000, 60,000 and 100,000 miles all act as real psychological barriers, so a car sitting just under one of these often achieves a noticeably better price.
Does unusually low mileage always mean a higher price?
Not automatically, no. Buyers can be wary of a car that's barely been driven, and genuine mechanical risks like perished seals and degraded fluids can develop on cars that sit unused, regardless of how few miles they've covered.
Does age or mileage matter more for a car's value?
It depends on the car's age. For cars under five years old, age tends to matter more. Past that point, mileage starts to play a considerably bigger role in the value gap between similar cars.
Does it matter if my mileage was mostly motorway or city driving?
Genuinely, yes. Stop-start city driving puts more mechanical strain on a car than the same distance at a steady motorway cruise, so two cars with identical mileage can be in noticeably different condition underneath.